Materials based on ceria (Ce02) are used in many catalytic applications
[2-5]. These applications make use of the unusual properties of ceria,
namely, the ability to shift between its two oxidation states, Ce(III) and
Ce(lV), and the high mobility of bulk oxygen species - properties that
allow ceria to behave as an oxygen buffer. It is important therefore that we
understand more fully how vacancies (surface vacancies are the sites of
catalytic activity) segregate to ceria surfaces and also how oxygen atoms
move in the ceria surface. In this study, we investigate vacancy
segregation and focus on studying transport at or near the {Ill} surface of
ceria, chosen because it is the most stable surface [8] and hence most
prevalent.
Many applications take advantage of the high oxygen storage capacity
(OSe) of ceria. We propose a new polycrystalline multilayered nanotube
structure that could go some way to further unlocking the oxygen storage
capabilities of the material. We illustrate how our simulation models are
constructed and further investigate the potential reactivity of the new
structure, by comparing predictions of vacancy cluster segregation
behavior to that predicted for the most stable flat {Ill} surface.